Home Secretary Charles Clarke and Tory leader Michael Howard were united today in moves to crush revolts over ID cards.

Mr Clarke faces a backbench Labour rebellion in his first major test since replacing David Blunkett last week.

But Mr Howard faces a potentially more damaging threat to his authority from Tories opposed to the scheme.

Former Education Secretary Mr Clarke took a bullish approach, insisting he would not waver in the face of "woolly liberal thinking".

Writing in a national tabloid, Mr Clarke says he is prepared to listen to "constructive" suggestions but rejected calls for a "pause" for reflection.

He added: "My commitment to the principle of ID cards is very strong and will not waver, mainly because I think that they will help to make everyone a little safer, as no real cost to civil liberties".

Mr Howard fought a Shadow Cabinet battle to convince senior colleagues to back the measure. He won only conditional backing and members of his team may still "go missing" rather than fall into line.

Writing in another national newspaper, Mr Howard argued it would be "irresponsible" to dismiss the scheme out of hand.

He promised a review of the scheme if the Tories take power but said police and security service chiefs had told him ID cards "can and will" help fight terror.

He added: "The threat to life and liberty from terrorism is so great that it would, in my view, be irresponsible to dismiss out of hand any proposals put forward for by the police and the security services to enhance security without listening to what they say."

Critics argue that introducing cards containing a microchip storing biometric details is a costly scheme with no specific aim.

Ministers insist it will help the fight against terrorism, organised crime and illegal immigration. But opponents say similar schemes in other countries have not prevented attacks such as the Madrid rail bombings and that, in any case, the cards will not be introduced until 2008.

They also warn that the Government's track record on hi-tech projects suggests it could prove a shambles.

Mr Clarke is expected to woo critics by vowing that officials who secretly access information to which they are not authorised will face up to two years in jail.

He is also expected to signal cut-price ID cards for the poor and pensioners - but that could push up the price, estimated at £85 for a card and passport, for middle-class voters.

Former Shadow Attorney-General Bill Cash said he believed disquiet over ID cards was "very deep" among senior Tories.

"There are former Cabinet ministers who have expressed serious reservations and, indeed, also members of the Shadow Cabinet, according to reports," Mr Cash told a radio programme.

"I think there will be significant resistance to these proposals."

Mr Cash rejected the argument that Mr Howard had to support the ID card proposals because he had tried to introduce them himself as Home Secretary in the mid-1990s.